Heart valve disease is a widespread condition in which one or more of the valves of the heart fails to function properly. Diseased heart valves may be categorized as either stenotic, wherein the valve does not open sufficiently to allow adequate forward flow of blood through the valve, and/or incompetent, wherein the valve does not close completely, causing excessive backward flow of blood or regurgitation through the valve when the leaflets are supposed to coapt together. Valve disease can be severely debilitating and even fatal if left untreated.
Various surgical techniques may be used to repair a diseased or damaged valve, including securing a cardiac implant to the diseased annulus. Cardiac implants include prosthetic heart valves, valved conduits and annuloplasty rings. In a valve replacement operation, the damaged leaflets are excised and the annulus sculpted to receive a replacement valve. Worldwide, approximately 300,000 heart valve replacement surgeries are performed annually, and about one-half of these patients received mechanical heart valves, which are composed of rigid, synthetic materials. The remaining patients received bioprosthetic heart valve replacements, which utilize biologically derived tissues for flexible fluid occluding leaflets. Prosthetic heart valves may be implanted independently in one of the orifices or annuluses of the heart, or may be coupled to a flow conduit which extends in line with the valve a predetermined distance. For example, valved conduits can be designed for reconstruction of portions of the flow passage above and below the aortic valve, such as the ascending aorta, in addition to replacing the function of the valve itself. Another less drastic method for treating defective valves is through repair or reconstruction, which is typically used on minimally calcified valves. One repair technique that has been shown to be effective in treating incompetence is annuloplasty, in which the deformed valve annulus is reshaped by attaching a prosthetic annuloplasty repair segment or ring to the valve annulus.
In a typical cardiac implant procedure, the aorta is incised and, in a valve replacement operation, the defective valve is removed leaving the desired placement site that may include a fibrous tissue layer or annular tissue. Known cardiac implant techniques include individually passing sutures through the fibrous tissue or desired placement site within the valve annulus to form an array of sutures. Free ends of the sutures are extended out of the thoracic cavity and are spaced apart, sometimes being distributed around a suture organizer. The free ends of the sutures are then individually threaded through a suture-permeable sealing edge of the annuloplasty ring or prosthetic heart valve. Once all sutures have been run through the sealing edge (typically 12 to 18 sutures), all the sutures are pulled up taught and the prosthesis is slid or “parachuted” down until it sits against the target annulus. The cardiac implant is then secured in place by traditional knot tying of the anchoring sutures on the proximal side of the sealing edge. This procedure is time consuming as doctors often use three to ten knots per suture.
During open-heart procedures, the patient is on heart-lung bypass which reduces the patient's oxygen level and creates non-physiologic blood flow dynamics. The longer a patient is on heart-lung bypass, the greater the risk for complications including permanent health damage. Existing techniques for suturing cardiac implants extend the duration of bypass and increase the health risks due to heart-lung bypass. Furthermore, the securing force created by suturing varies significantly because the pre-tensioning of the suture just prior to knot tying is difficult to consistently maintain, even for the same medical professional.
There exists a need for devices and methods that reduce the time required to secure a heart valve repair prosthesis in place. Currently a clinician must tie a multitude of knots in sutures which can take a great deal of time and lengthens the time a patient is on cardio-pulmonary bypass and under anesthesia. Additionally, there exists a need to make it easier to secure a heart valve repair prosthesis (e.g., an annuloplasty ring) in place. Currently, a clinician must work in the limited space near the heart to tie knots in sutures. This is a cumbersome process that benefits from a clinician of great dexterity and patience.